Her mother, a realtor based in Smyrna, Georgia, isn’t the only one trying in vain to get at Julia Roberts these days. Since last May, when the news broke that the world’s highest-paid actress was pregnant with twins, her expanding belly has gotten so much press attention that you’d think she was hiding Osama bin Laden in there. Roberts, as usual, has been mum about the details—which is why it’s rather astounding that this interview is not taking place in the generic confines of a publicist’s office or a hotel suite, but in a hospital room in Los Angeles, where Roberts is lying flat on her back, dressed in sweatpants and a white T-shirt. After experiencing contractions several weeks before her due date, Roberts rushed here with her husband, Danny Moder, from their home near the beach. The doctors placed her on temporary bed rest, and so for now she’s forgoing Pilates classes in favor of endless rounds of Scrabble.

Why would the famously private Roberts invite a magazine writer to come hang with her in the maternity ward? Maybe she wants to make good on her earlier promise of a face-to-face interview; maybe she’s just bored after watching one too many DVDs. Or maybe, as director Mike Nichols points out, she’s acutely aware of the power of her own charisma, and she realizes that her charms might not be fully apparent on the phone. “I think Julia is a genius at how to be with people,” says Nichols, thinking back to how elated he was after meeting the actress for the first time, to discuss a starring role in his new film, Closer. “It’s something she has a very rare understanding of, and gift for.”

Still, Nichols adds, pity the naive journalist who walks into an interview with Roberts and actually expects her to share any intimacies. He recalls a moment from the actress’s November appearance on Oprah, when she was asked a personal question about pregnancy’s effect on her hormones. Roberts let rip with a hyenalike laugh that stirred the audience into an almost freakish frenzy of delight. Then she seamlessly changed the subject. “You didn’t realize until 10 minutes later that she never answered the question,” Nichols says. “That’s another part of her genius. She gives you a great time, but she gives up nothing.”

Today, despite being attached by pink nylon straps to two heart monitors (one for her future daughter, one for her son), Roberts does an impressive job of churning out the charm, even when a nurse steps in to take her blood pressure and administer pills. (“I feel like I’m 12,” she says.) At one point she whips off the purple silk prayer shawl that’s draped over her middle to reveal her bare belly in all its fertile glory. Reaching over toward the machine next to the bed, she successively turns up the volume on each of the two monitors, filling the room with the squishy pulsing sounds of tiny human hearts. “Listen,” she says. “That’s her. And that’s him. Isn’t that amazing?”

If her emergency trip to the hospital was the scariest moment of her pregnancy, then Roberts is downplaying it now. “I think I knew that everything was going to be okay,” she says. “This is all par for the course. It’s nothing particularly surprising, or dramatic, or tragic.”

Anyone hankering for surprise, drama, or tragedy, or all three at once, need look no further than Roberts’s latest movie. Based on the acclaimed play by Patrick Marber, Closer follows four attractive Londoners (Roberts, Natalie Portman, Jude Law and Clive Owen) as they fall in and out of love with one another while driving themselves mad with anguish. Roberts’s character, a photographer and adulteress named Anna, is perhaps the most selfish and manipulative of the bunch.

It took a while for the actress to warm to her. “Whenever you are faced with someone who has made far more errors in judgment and far more mistakes than you,” she says, “you have a tendency to get on your high horse.” Ultimately, Roberts accepted the role in large part because of Nichols, who, with such films as The Graduate, Carnal Knowledge and HBO’s Angels in America, has proved himself to be a wittily sophisticated explorer of the darker depths of human nature. (Nichols had initially cast Cate Blanchett as Anna but approached Roberts after Blanchett got pregnant and had to drop out.) “The movie is so completely and utterly adult and intense,” Roberts says, “so different than anything I ever do, or even get asked to do, frankly. I wouldn’t think of me for it.”

If there’s one scene that will simultaneously impress the critics and test the loyalty of her PG-13 fan base, it’s the climactic face-off with her husband (Owen), in which he learns of her yearlong affair with Law’s character. Desperately hurt, and searching for a way to make himself hate his wife, he forces her to recount all her adulterous escapades in graphic detail, even grilling her on the taste of his rival’s semen.

So how much fun was that?

“Horrible,” Roberts says with a shiver. “We called it The Scene. I had so many different reactions to it. We rehearsed it once, and I just wept through the whole thing. The next time, I laughed through it. I was really glad when it was done.”

According to Nichols, shooting that scene “sort of ripped up everybody who was on set”—especially Roberts, which helps explain why her performance is so riveting. “With Julia, it’s not pretending,” he says. “She’s living it as she does it. She’s an actress who actually blushes in scenes. And if she blushes once, she does it in every take.”

It remains to be seen what effect, if any, Closer will have on Roberts’s career trajectory. What’s certain is that in the past, whenever Roberts has made films that have alienated her legions of mainstream fans, she’s never had much trouble winning them back. In the mid-Nineties, a few years after her breakout success in Pretty Woman, there was a period when she played a string of sourpusses in a string of flops (Mary Reilly chief among them). Things got so bad that Sandra Bullock was called in to temp as America’s Sweetheart, until Roberts beamed her way back with My Best Friend’s Wedding in 1997, proving that her box-office power was directly proportional to the amount of screen time given to her mile-wide smile. But Oscars aren’t won on good dentistry alone, and Roberts’s 2001 victory for her turn as Erin Brockovich proved that she’d become that rarest of creatures, a true star who’s also a true actress.

All along, Hollywood’s top executives have been trying to figure out what it is, exactly, that makes Roberts connect so well with the public, and why the Gwyneths and Nicoles and Reeses of the world can’t always pull in the same crowds on opening weekend. Certainly it has something to do with Roberts’s goddess-next-door looks, which ensure that men will love her and women won’t loathe her—and with that gangly, just-a-girl-from-Smyrna charm she’s managed to maintain even while socking away up to $22 million per movie. Whenever Roberts walks up a red carpet, you sense that she’s convinced she’ll trip on it, even though you know she won’t.

Meanwhile, the search for “the next Julia Roberts” continues apace, and Roberts herself has an idea about why it’s not succeeding. She doubts she’d fit the bill if she were starting again as an ingenue.

“I’m glad I’m not up-and-coming in the world of show business today,” she says. “I don’t think I would be well suited, at 20, to navigate it. I mean, the media is such a different animal now. It’s ugly in a way that I guess I don’t understand. For these young girls, everything’s just so crazy and kinetic and scary.” Part of the problem, she says, is that the hype cycle spins so quickly that audiences tire of newcomers even before figuring out who they are. “Everybody’s sort of shoved down your throat,” she says. “You’re not allowed to really sit back and appreciate people very well.”

With more than 30 films on her résumé, Roberts feels she’s earned the right to do what interests her, rather than what’s expected of her. Besides, she insists that she’s never made any deliberate attempt to satisfy mainstream audiences, adding that, as a moviegoer who’s a sucker for comedies and thrillers, she’s part of the mainstream herself. “Being in a good comedy is…it’s just fun,” she says. “It’s something my personality type really responds to. I can get really excited about it, just as I can get excited about a good dramatic piece.” As it happens, anyone experiencing smile deprivation after seeing Roberts in Closer need only walk to the next line at the multiplex for Ocean’s Twelve, the breezy crime sequel in which Roberts reprises the role of Tess Ocean. This time she gets a little more action, joining the guys in a high-concept heist of a Fabergé egg.

Roberts’s most vivid memories from the shoot don’t involve tearful rehearsals (or any rehearsals at all), but raucous dinners on the shores of Lake Como with George Clooney and Brad Pitt. For a moment, Roberts can’t even remember whether her character is pregnant in the film. “Am I pregnant? No. Am I? I think I am. Okay, wait. I’m on medication!” Roberts laughs, clamps her eyes shut and puts her fingers to her temples in an effort to concentrate. “Well, things got changed around a lot. I don’t think I am pregnant. It’s set three years after the first movie, and George and I are back together. We’re married. I think we were always married. I don’t think we ever actually got divorced.”

Her confusion is perhaps understandable, since Tess’s fictional pregnancy is now overshadowed by Roberts’s own very real one. It’s an experience that she can’t seem to find enough superlatives for. “Overall it’s been sooo easy and happy,” she says. “I haven’t been weepy or angry, just on this happy high all the time. I am a total 24-hour giggle box.” According to CAA agent Kevin Huvane, who’s been tight with Roberts since they met by chance in a New York restaurant 20 years ago, Roberts’s pregnancy is the ultimate expression of her “incredibly maternal” nature. “She has always wanted to be a mother,” Huvane says. “And she wouldn’t tell you this, but she acts like a mother to many people, taking care of them emotionally and financially. She’s very loyal, and she’s ferocious in her loyalty—like a mama bear to many cubs.”

For a long time, one of the biggest mysteries about Roberts (for her fans, at least) was why the joyfulness that she so effortlessly radiated onscreen seemed elusive in her personal life. Like Closer—which focuses on the stormy beginnings and endings of relationships while skipping over the more comfortable, if less dramatic, periods in between—Roberts’s romantic history seemed to be all ups and downs, with very few happy mediums. “I mean, the 20s are tricky,” is all she’ll say. “But I think if you had met me in my 20s, you would have thought I seemed happy then too.”

Roberts celebrated her 37th birthday here in the hospital, where the walls are still decorated with ribbons and wrapping paper from the gifts Moder and their friends brought over. As she waits out the last weeks before giving birth, she says, “I think that it is safe to say now that I am fully and completely a grown-up. Definitely. And I think the last phase of my security in who I’ve become, as this grown-up girl, has come with my relationship with Danny, and what that has instilled in me. It’s kind of that last piece to the puzzle.”

Although Roberts hasn’t exactly shown a discernible pattern in her choice of men (the spectrum has been wide enough to include both Lyle Lovett and Benjamin Bratt), Moder, who’s been spending every night in the hospital with his wife, seems different from all of them. For one thing, he’s not an entertainer but a cinematographer and all-around low-key guy who surfs every day. (“I think he’s part dolphin or something,” Roberts says.) Is it a relief that he’s not an actor?

Roberts grimaces. “That’s like asking, ‘Are you glad he is not another person?’” she says. “I mean, I am completely happy with my life. I love everything about it.” Impending motherhood, she says, has taught her a lot about the serenity that comes with surrendering to fate. “I believe in the will of heaven,” she says. “And I believe, at this moment in my life, that to have kids is just really perfect. The way my life is changing seems like a natural shift to me. I am almost not perfectly aware of it because it seems like it is as it should be.” (Just as this issue went to press, Roberts gave birth to son Phinnaeus Walter and daughter Hazel Patricia.)

Postpregnancy, Roberts plans to take a similar Zen-like approach to her career, though she was surprised at the reaction to a remark she made to Newsweek last summer about the impossibility of predicting her next move. “Everybody was like, ‘She’s retiring!’ It was like the shot heard ’round the world,” she says. “I had a man come up to me in the market and say, ‘Oh please, don’t tell me you are not going to make any more movies!’ It was so sweet. I said, ‘I’m not going anywhere.’”

She does say that from now on, in order for her to sign up for a film, “the script will have to blow me away. The babies will be a great factor, like anything that makes your life more interesting and more enjoyable. Scripts will have to continue to compete with the quality of my life.”

There are no piles of scripts in Roberts’s hospital room today; only a few novels, including Kent Haruf’s Plainsong, along with some knitting. She’s currently finishing up a baby sweater but will soon stop making things for her kids, she says. “I am going to wait and see what they like.” She’ll wait and see about everything else too. The one certainty is that as soon as she and Moder can, they’ll fly back to their ranch in Taos, New Mexico, where Phinnaeus and Hazel will join their clan of eight dogs adopted from the pound.

“There’s no real plan,” Roberts says. “We’ll just go along like we always have. Except there will be more of us.”